[LLVMdev] Emit 4-byte-displacement jump instructions instead of short one-byte-displacement jump instructions, when generating machine code, under x86_64

Yue Chen ychen.contact at gmail.com
Fri Mar 13 13:42:36 PDT 2015

Dear all,

We are working on a research project based on LLVM. I wonder if there is
any easy way to make LLVM
NOT emit short jump instructions with 1-byte-displacement, like "75 30
 JNE +30", "eb 1a   JMP +1a", etc;
instead only emit 4-byte-displacement jump instructions with 3-byte zero
paddings, like
"0f 85 30 00 00 00   JNE +30", "e9 1a 00 00 00    JMPQ +1a", etc., under
the x86_64 architecture.
Apparently, this would increase the code size.

Best regards and thanks,
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150313/1957c864/attachment.html>

More information about the llvm-dev mailing list